Aptitude - Clock - Discussion

Guys to solve the angle between the hour hand and the min hand :

For Ex:

Let the time be 8:30 so that the hour hand is slightly far from 8 and the min hand points exactly on 6. Then the degrees between two no. S is 30 degrees (hour hand).

Now, the angle between hour hand (approximately at 8) and at 6 (min hand) is 60 degrees. Now consider only the min hand (on 6).

Now do k*30 (30 because the min hand is at 6 and k is a constant having a value of 0.5). Therefore it becomes 30*0.5 gives 15 degrees. Add these 15 degrees to 60 degrees which we got earlier. Therefore it become 60+15 = 75 degrees.

Explanation is big but am sure I will understand.

Hi @ALL

We can write 8.30 as 17/2 hours.

Let me explain.

17/2 = 8.5 = 8 hours + 0.5 hours

= 8 hours + 1/2 hours

= 8 hours + 1/2 x 60 mins (.: 1 hour = 60 mins, Therefore, 1/2 hours = 30 mins)

= 8 hrs 30 min.

Therefore, we can write 8-hrs 30-min as 17/2.

While solving problems, make all numbers in vulgar fraction, it will be easy to solve problems quickly.

For example: 360/12 x 17/2 = ?

It is easy to solve. Have a nice day!

Look at the clock -_- it simply can't be 75 deg it has to be 60deg.
Since 6-9 is 90deg.

And can be divided in 3 intervals.
i.e. 6-7 , 7-8, 8-9.

So obviously u divide 90 by 3 ie. 30deg each.
So when its 8:30.

Hour hand on 8.
Minute hand on 6.

So it covers 2 intervals of 30deg.
HENCE 60 degree

Clock is divided into 60 equal minute division.

1 minute division = 360/60 = 6 degree. So for 8:30.

Minute hand is on 6 while hr hand is in middle of 8 and 9.

6-7 = 5min = 5*6 = 30 degree.

7-8 = 30min.

8-8.5 = 15 min.

Total angle = 6-7+7-8+8-8.5.

= 30+30+15.

= 75 degree.

It is very easy new method.

In 1 minute your hand covers 1/2° while minute hand 6°.

Multiply 30 (1/2) for degree covered by your hand =15°.

And 10 min (6°) for degree by minute hand=60°.

Just add them 60+15=75°.

Any doubts.

Here we have to find angle b/w 8.30.

The speed of minute hand= 6.
The speed of hour hand = 0.5.

The distance b/w each no is =30 i.e, 360%12 = 30;.

Sol : Hour hand: 8*30 = 240.
And 30*0.5 = 15.
Minute Hand
30*6 = 180.
255 - 180 = 75.

Hours hand should be calculated by considering
hours Hand -( 8 * 360/12)= 240 deg
Minutes Hand - ( 30 * 360/60) = 180 deg

Total angle b/w Hour and Min = 240 -180 = 60 deg.

This is Practically as per the clock system.

We can use this formula for this type of questions.

Angle= 30H - (11/2)*M.
Where H is hour and M is minute.
So, 30*8- (11/2)*30 = 75 ans.

Note: If the answer is minus then ignore minus or reverse this formula.

Just do this:

8.30 = 8.00 + 0.30 (Hours + Minutes).

Ignore the decimal part in 0.30.

Convert 30 min in hrs

30/60 = 1/2 hrs

Now add 8+1/2 = 17/2

Just remember the angle traced by formulae.

To find the angle between the times 1.05,2.10,3.15,4.20,5.25, 6.30,7.35,8.40,9.45,10.50,11.55 and 12.60 only takes the half of the minutes.

For 1.05=2.50, 2.10=5 and so on.